The invention relates generally to projection screens and more specifically to a diffuser-coated projection screen element and method of manufacture.
Large projection screens are known in the art but typically are either poor in quality due to poor diffusion characteristics or prohibitively expensive to produce in large quantities. Generally, the assembly of large, high-quality projection screens is difficult and labor intensive because more than one layer must be assembled into a single screen. Large, high-quality projection screens generally require, for example, assembly of layers within a bracket and/or adhesion and/or lamination of one or more layers with optically clear adhesives. The costs associated with assembling large, high quality projection screens have hindered their mass production. Furthermore, due to the large size of the individual assembly layers, these layers often bow, buckle and/or pop out of the assembly over time. Finally, high-quality large projection screens are difficult to transport and/or store efficiently because they typically cannot be folded or rolled.
A large, high-quality projection screen element has been developed that may be mass-produced and is stable over time because the diffusion layer is coated directly onto a substrate. Coating the diffusion layer onto the substrate eliminates the need to affix the diffusion layer with adhesives or assemble the layers into a bracket, which is labor intensive. The element is stable because the diffusion layer is coated and therefore will not easily bow or buckle from the substrate. Also the projection screen element of the present invention may be folded, rolled or wound about a cylinder so that it may be stored easily and efficiently.
In one aspect of the present invention, a projection screen element is provided that comprises a substrate and a diffusion coating disposed on the substrate. The diffusion coating comprises a matrix having a first index of refraction and a plurality of particles having a second index of refraction disposed within the matrix. The substrate may be translucent for a rear projection screen element, or reflective for a front projection screen element.
In another aspect of the present invention, a method for making a projection screen element is provided comprising the following steps: providing a substrate; providing a matrix material; providing a dispersion material having an index of refraction different from that of the matrix material; dispersing the dispersion material and the matrix material to form a mixture; and coating a surface of the substrate with the mixture.
The invention will be understood further upon consideration of the following drawings, description and claims.